Merge #605

605: Merge both module classes in one r=philberty a=CohenArthur

This PR merges both kinds of Modules (formerly `ModuleBodied` and `ModuleNoBody`) as one class with an enum. This is the [behavior used by rustc](https://github.com/rust-lang/rust/blob/2939249f294dd54a9ce78a8ee1f2922a44e7fb7c/compiler/rustc_ast/src/ast.rs#L2274), where both variants are kept in an enum with one holding a vector of items.

This change is important for multiple file parsing: An external mod (`mod foo; // defined in foo.rs or foo/mod.rs`) will see its items expanded during expansion, which occurs after parsing. This means that the previous directive will be "replaced" by `mod foo { <items> }` at the AST level. In order to achieve this, we need to be able to modify a previously parsed instance of an AST element.

In rustc, this is done [here](https://github.com/rust-lang/rust/blob/2939249f294dd54a9ce78a8ee1f2922a44e7fb7c/compiler/rustc_expand/src/expand.rs#L1427), where `mod_kind` was previously `ModKind::Unloaded` and becomes `ModKind::Loaded(parsed_items, ...)`. 

Co-authored-by: CohenArthur <arthur.cohen@epita.fr>

1 files changed, 9 insertions, 27 deletions

diff --git a/gcc/rust/ast/rust-ast-full-test.cc b/gcc/rust/ast/rust-ast-full-test.cc
index 5d32139..dfd9cdb 100644
--- a/gcc/rust/ast/rust-ast-full-test.cc
+++ b/gcc/rust/ast/rust-ast-full-test.cc
@@ -379,22 +379,20 @@ VisItem::as_string () const
 std::string
 Module::as_string () const
 {
-  std::string vis_item = VisItem::as_string ();
+  std::string str = VisItem::as_string () + "mod " + module_name;
 
-  return vis_item + "mod " + module_name;
-}
-
-std::string
-ModuleBodied::as_string () const
-{
-  // get module string for "[vis] mod [name]"
-  std::string str = Module::as_string ();
+  // Return early if we're dealing with an unloaded module as their body resides
+  // in a different file
+  if (kind == ModuleKind::UNLOADED)
+    return str + "\n no body (reference to external file)\n";
 
   // inner attributes
   str += append_attributes (inner_attrs, INNER);
 
   // items
   str += "\n items: ";
+
+  // This can still happen if the module is loaded but empty, i.e. `mod foo {}`
   if (items.empty ())
     {
       str += "none";
@@ -419,16 +417,6 @@ ModuleBodied::as_string () const
 }
 
 std::string
-ModuleNoBody::as_string () const
-{
-  std::string str = Module::as_string ();
-
-  str += "\n no body (reference to external file)";
-
-  return str + "\n";
-}
-
-std::string
 StaticItem::as_string () const
 {
   std::string str = VisItem::as_string ();
@@ -4053,7 +4041,7 @@ AttrInputMetaItemContainer::as_string () const
 /* Override that calls the function recursively on all items contained within
  * the module. */
 void
-ModuleBodied::add_crate_name (std::vector<std::string> &names) const
+Module::add_crate_name (std::vector<std::string> &names) const
 {
   /* TODO: test whether module has been 'cfg'-ed out to determine whether to
    * exclude it from search */
@@ -5381,13 +5369,7 @@ Method::accept_vis (ASTVisitor &vis)
 }
 
 void
-ModuleBodied::accept_vis (ASTVisitor &vis)
-{
-  vis.visit (*this);
-}
-
-void
-ModuleNoBody::accept_vis (ASTVisitor &vis)
+Module::accept_vis (ASTVisitor &vis)
 {
   vis.visit (*this);
 }